Merge nucleic/sleek-thistle-egret-fyej into dev

brush-core/src/expansion.rs

@@ -37,6 +37,11 @@ pub(crate) struct ExpanderOptions {
     /// Whether to perform pathname expansion (globbing). If disabled, glob patterns
     /// are returned as literal strings.
     pub pathname_expand: bool,
+    // nash: whether literal (unquoted, non-expansion) text is also subject to
+    // field splitting. Off by default per POSIX/bash (only expansion results
+    // split); enabled by callers whose input string is *data*, e.g. the
+    // `compgen -W` word list.
+    pub field_split_literal_text: bool,
 }
 
 impl Default for ExpanderOptions {
@@ -46,6 +51,7 @@ impl Default for ExpanderOptions {
             brace_expand: true,
             execute_command_substitutions: true,
             pathname_expand: true,
+            field_split_literal_text: false,
         }
     }
 }
@@ -333,6 +339,15 @@ impl ExpansionPiece {
             Self::LiteralText(s) => Self::Unsplittable(s),
         }
     }
+
+    // nash: opt literal text into field splitting (see
+    // `ExpanderOptions::field_split_literal_text`). Quoted pieces stay intact.
+    fn make_literal_splittable(self) -> Self {
+        match self {
+            Self::LiteralText(s) => Self::Splittable(s),
+            other => other,
+        }
+    }
 }
 
 enum ParameterState {
@@ -532,6 +547,8 @@ struct WordExpander<'a, SE: extensions::ShellExtensions> {
     in_double_quotes: bool,
     /// Whether to use heredoc expansion semantics (literal quotes, no brace expansion).
     heredoc_mode: bool,
+    // nash: see `ExpanderOptions::field_split_literal_text`.
+    field_split_literal_text: bool,
 }
 
 impl<'a, SE: extensions::ShellExtensions> WordExpander<'a, SE> {
@@ -547,6 +564,7 @@ impl<'a, SE: extensions::ShellExtensions> WordExpander<'a, SE> {
             disable_pathname_expansion: false,
             in_double_quotes: false,
             heredoc_mode: false,
+            field_split_literal_text: false,
         }
     }
 
@@ -572,6 +590,7 @@ impl<'a, SE: extensions::ShellExtensions> WordExpander<'a, SE> {
             disable_pathname_expansion: !options.pathname_expand,
             in_double_quotes: false,
             heredoc_mode: false,
+            field_split_literal_text: options.field_split_literal_text,
         }
     }
 
@@ -802,6 +821,13 @@ impl<'a, SE: extensions::ShellExtensions> WordExpander<'a, SE> {
         // Go through the fields we have so far.
         for existing_field in expansion.fields {
             for piece in existing_field.0 {
+                // nash: callers whose input is data (e.g. compgen -W) opt
+                // literal text into splitting.
+                let piece = if self.field_split_literal_text {
+                    piece.make_literal_splittable()
+                } else {
+                    piece
+                };
                 match piece {
                     // nash: literal text is never field-split (only expansion
                     // results are), but stays a distinct piece so its glob
@@ -937,7 +963,19 @@ impl<'a, SE: extensions::ShellExtensions> WordExpander<'a, SE> {
                 ExpansionPiece::Unsplittable(self.expand_tilde_expression(&tilde_expr)?),
             ),
             brush_parser::word::WordPiece::ParameterExpansion(p) => {
-                self.expand_parameter_expr(p).await?
+                // nash: whatever a parameter expansion substitutes (including
+                // literal text from ${v:-default} / ${v:+alt} words) is an
+                // expansion *result*, so it is subject to field splitting.
+                // Quoted pieces inside remain Unsplittable.
+                let mut expansion = self.expand_parameter_expr(p).await?;
+                for field in &mut expansion.fields {
+                    for piece in &mut field.0 {
+                        if let ExpansionPiece::LiteralText(s) = piece {
+                            *piece = ExpansionPiece::Splittable(std::mem::take(s));
+                        }
+                    }
+                }
+                expansion
             }
             brush_parser::word::WordPiece::BackquotedCommandSubstitution(s)
             | brush_parser::word::WordPiece::CommandSubstitution(s) => {